Not to be cited without permission of the authors 1 Canadian Atlantic Fisheries Scientific Advisory Committee CAFSAC Research Document 85/8 Ne pas citer sans autorisation des auteurs l Comite scientifique consultatif des peches canadiennes dans l'atlantique CSCPCA Document de recherche 85/8 Analysis of the Snow Crab, Chionoecetes opilio, Fishery in Newfoundland for by D. M. Taylor and P. G. O'Keefe Fisheries Research Branch Department of Fisheries and Oceans P.O. Box 5667 St. John's, Newfoundland Ale 5Xl 1 This series documents the scientific basis for fisheries management advice in Atlantic Canada. As such, it addresses the issues of the day in the time frames required and the Research Documents it contains are not intended as definitive statements on the subjects addressed but rather as progress reports on ongoing investigations. Research Documents are produced in the official language in which they are provided to the Secretariat by the author. 1 Cette serie documente les bases scientifiques des conseils de gestion des peches sur 1a cote atlantique du Canada. Comme te'le, elle couvre les problemes actuels selon les echeanciers voulus et les Documents de recherche qu'elle contient ne doivent pas etre consideres comme des enonces finals sur les sujets traites mais plutot comme des rapports d'etape sur les etudes en cou rs Les Documents de recherche sont publies dans 1a langue officielle utl1isee par les auteurs dans le manuscrit envoye au secretari at.
2 Abstract Population size estimates for snow crab (Chionoecetes opilio) off the east coast of Newfoundland, based on Leslie analyses, are presented for the fishing season. Within given crab management areas, estimates of population size ranged from 209 to 2023 mt and exploitation rates from 36 to 91%. Resume On presente des estimations de 1'effectif de la population de crabes des neiges (Chionoecetes opilio) au large de la cote est de Terre-Neuve pour la saison de peche. Ces estimations sont fondees sur les analyses de Leslie. Selon la zone de gestion consideree, l'effectif de la population varie de 209 a 2023 tm et le taux d'exploitation, entre 36 et 91 %.
. 3 Introduction Snow crab (Chionoecetes opilio) landings peaked in at 13,838 mt. Despite an increase in effort and e discovery of new offshore fishing grounds, landings declined in to 13,178 mt along with a corresponding decrease in CPUE in almost every management area (Fig. 1). This trend in the fishery continued in with landings further reduced to 11,180 mt. This dramatic drop in landings can largely be attributed to a great reduction in effort and CPUE in the Southern Zone (Areas 8-25, Fig. 1). The reduction in effort (trap hauls) is due to severe ice conditions and inclement weather. However, the dramatic reduction in CPUE experienced by vessels prosecuting the fishery in the southern zone certainly affected overall landings. Several vessels indicated that CPUE became so low that they gave up crab fishing in order to fish mackerel. Effort and landings in the northern zone (Areas 28-40) increased markedly in primarily due to the issuance, of nine new permits, the holders of which directed most of their efforts at previously unfished areas. There was also some expansion of effort within Area 34 caused by movement of vessels that traditionally fished in Area 32 onto Area 34 grounds. Generally, the outlook for the southern zone, particularly in the offshore areas, is worse than the bleak forecast expressed by the authors prior to the commencement of the season (Taylor and O'Keefe ). It is too early as yet to forecast the overall future of the fishery in the northern zone until the extent and viability, of the new fishing grounds is determined. Materials and Methods Catch/effort data from fishermen's logbooks were analyzed and data for each management area compared to processors' sales slips in order to check the accuracy of the logbooks. From these data biweekly catch/effort tables were constructed for each management area in order to determine whether Leslie analysis was feasible. In previous assessments of Newfoundland snow crab populations the authors reported excellent logbook coverage for all management areas (Taylor and O'Keefe, ). Unfortunately, during certain factors which have been discovered have caused us to doubt the veracity of many of the logbooks submitted, in particular, those from the southern zone. Due to the sporadic nature of fishing effort and reduced CPUE and landings, fish processors have been forced to average, on a weekly basis, fishermen's landings. This ensures that fishermen qualify for maximum unemployment benefits in the off-season. As a result of the processor's misreporting of landings, data on CPUE must be viewed as suspect. Also, many fishermen admitted during interviews that due to low CPUE they had been forced to disregard the regulation which limits fishing activity to 800 traps per day, and out of fear of prosecution had felt it necessary to misreport daily effort in their log books.
4 Nevertheless, Leslie analysis has been carried out for eight management areas. The results of these analyses are summarized in Table 1 and individual analyses are illustrated in Figures 2-9. Southern Zone Results and Discussion Examination of Table 1 shows that in, not only is the CPUE for all areas drastically reduced but in areas where Leslie analyses have been conducted, biomass estimates are much lower than in previous years..it was impractical to attempt Leslie analyses for Areas 18 and 15 due to a drastic reduction in effort. An attempt was made to perform Leslie analyses for Area 16, however, the necessary decline in catch per effort over the course of the fishery did not occur in due to the fact that many vessels landed large numbers of soft-shelled animals, which, in spite of prohibitive regulations, were purchased by the processors. Again in all inshore areas experienced a high incidence of softshelled animals for much of the season. Once again, we recommend a reduction in effort in Areas 8, 12, 14, 19, and 25. Although the biomass estimate for Bonavista Bay indicates an increase over the estimate, it is noteworthy that effort more than doubled over while CPUE was almost halved. Northern Zone Three areas, 28, 30, and 38, were fished for the first time in. Initial results are encouraging; particularly so in that almost all fishing was conducted by nine newly licenced vessels with inexperienced crews. Effort dropped in Area 32, as did landings since much of the effort traditionally directed at this area switched to Area 34. Despite this decline in effort and landings, CPUE was also reduced over levels (Table 1). In both Areas 34 and 36 effort doubled while CPUE dropped from levels. Effort should be held at current levels in Area 34. Fishermen from both areas experienced a high incidence of soft-shelled animals. Conclusions was a disasterous year for the crab fleet in the southern zone. The dramatic drop in CPUE for all management areas plus an apparent lack of
5 recruitment in the offshore areas indicate that the fishery may be in a state of decline. The Northern Zone appears to be very productive but declining CPUE in all areas indicates that in traditionally fished areas effort should not be increased. References Taylor, D. M., and P. G. O'Keefe.. Assessment of snow crab (Chionoecetes opilio) stocks in Newfoundland, 1979. CAFSAC Res. Doc. 81/57.. Assessment of snow crab (Chionoecetes opilio) stocks in Newfoundland in. CAFSAC Res. Doc. 83/3.. 1984. Assessment of Newfoundland snow crab (Chionoecetes opilio) stocks,. CAFSAC Res. Doc. 84/13.
6 Table 1. Summary of statistics for the Newfoundland Snow Crab fishery, 1979-83. Effort LandIngs CPUE Estimated biomass (mt) Exp loltatlon Area Year (trap hau Is) (mt) (kg/trap haul) (confidence limits) rate (%) 8 1979 1,260 11,150 48,350 37,780 8 168 506 274 6.7 15.0 10.5 7.3 10 3,080 43 13.9 12 13 14 1979 15 16 1979 18 1979 19 20 1979 22 1979 13,825 45,455 49,975 99,280 7,295 61,089 37,950 5,860 27,113 32,320 23,165 18,128 66,949 1,320 28,845 56,393 43,546 60,753 64,175 398,939 236,417 413,815 153,238 71,905 65,978 218,356 150,432 4,165 4,550 14,970 10,535 12,120 56,887 58,160 24,782 13,755 20,065 292 854 732 955 114 733 762 121 434 465 190 404 1056 138 464 869 502 694 564 6870 4944 6769 1847 473 1840 4194 1662 67 59 110 65 72 569 494 178 95 107 21.1 18.9 14.7 9.6 15.6 12.0 20.1 20.6 16.0 14.4 8.2 22.3 15.8 10.5 16.1 15.4 11.2 11.4 8.8 17.2 20.9 16.4 12.1 6.7 28.0 19.2 11.0 16.0 12.9 7.4 6.1 6.0 9.9 8.5 7.2 6.9 5.3 551 341 377 1291 974 1045 1095 614 209 (500-646) (306-409) <:511-128) (1114-1639) (938-1017) (948-1316) (891-1681> (506-1043) <181-260) 92 80 78 66 75 91 70 71 91 1861 (1465-3024) 56 1351 1571 689 1073 14359 14166 11289 7744 2016 1467 912 (951-3204) <1214-2890) (619-747) (951-1255) (1',778-19,792) (9348-59867) (910-17067) (5983-12022) (1684-2739) (1011-3233) <788-1103) 34 55 73 65 44 46 60 54 82 39 54
7 Table 1. Continued. Effort Landings CPUE Estimated btomass (mt) Exploitation Area Year (trap hauls) (mt) (kg/trap hau I) (confidence limits) rate (~) 24 & 26 1979 173,305 1586 9.2 24 & 26 191,754 1905 9.9 24 & 26 171,685 1376 8.0 25 96,330 905 9.4 1391 ( 1054-2445) 65 25 205,353 1101 5.4 1802 <1434-2914) 61 28 28,169 387 13.7 30 163,138 1470 9.0 32 1979 34 1979 1979 46,183 33,261 54,416 130,305 88,288 11,830 7,330 19,250 51,347 105,756 21,298 17,664 19,840 32,917 68,497 491 374 650 1352 537 141 96 322 735 1210 156 158 230 418 583 10.6 9.9 11.9 10.4 6.1 1 1.9 14.3 16.7 14.3 11.5 7.3 8.8 11.6 12.7 8.5 38 66,123 681 10.3 882 (76-1077) 787 (583-1229) 1845 (1193-6615) 2213 (1605-4284) 1097 (845-1874) 106 (74-273) 604 (502-792) 1016 (839-7423) 2023 (1632-3023) 383 (265-887) 276 (218-412) 504 (403-710) 1619 ( I 099-4692 ) 56 43 35 42 49 91 53 68 60 41 57 46 36
8 600590 580 57 56 550 540 530 520 51 50 I t 41 52 52 51 42 40 51 e 7 50 44 38 34 tz.36 :30 50 32,. $ 28. 49 ;: 25 17 49 0 NEWFOUNDLAND 2 2 19 480 18 48 2 ^'^ 14 13 47 0 4 6 & 8 47 10 12 46 59 058 57 56 550 540 530 52 5I" Fig. 1. Newfoundland snow crab management areas.
17.M AR.-APR(LI MAY I JUNE IJUL'TIAUd SEPT.-NOV. 16 15 14 13 12 Y.=16.58+(-4.858x10-5)X r2:0.80 ^c=80 B,= 341 mt (305-409) 11 - -J a I0 9 Y 8e w 7 Q_ O v 6 e ld 5 4 2 0 0. 50 100 150 200 250 300 350 400 CUMULATIVE CATCH (mt) Fig. 2 Leslie graph of biweekly catches of snow crab from St. Mary's Bay (Area 8) Newfoundland,.'
10 17 APRIL MAY JUNE JULY SEPT.-NOV. IS 15 14 13 -II -I ::::> ~ 10 0... : 9 I ';;.8... I.IJ 7 ::::> 0... u 6 5 4 Y:30 06+{-2 88IxI0-5 1X rz : 0 83 IL : 91 Bo:: 1043 mt (942-1347) 3 2 0 a 100 200 300 400 500 600 700 800 900 1000 1100 CUMULATIVE CATCH 1m!) Fig. 3. Leslie graph of biweekly catches of snow crab from Southeastern Avalon (Area=12) Newfound' and,
" 0 20 40, 60 80 roo 120 140 160 180 200 220 ' CUMULATIVE CATCH (mt). Fig. 4. Leslie graph of Qiweekly catches of snow crab from Eastern Avalon (Area 14) Newfoundland,.' '
12 20 19 18 MAY JUNE JULY SEPT. -NOV_ 17 16 15 ::; 12 :::> <I: :r; I 1 a.. <I: := 10... :9 l&j 8 :::> a.. u 4 y : 20-63+(-I-024x 10-s)X r2: 0-a9 Jl. : 82 Bo: 2016 mt (1684-2739) 3 2 -- 0 0 200 I 400 600 800 1000 1200 1400 1600 2000 CUMULATIVE CATCH (mtj 1800 2200 Fig. 5. Leslie graph of biweekly catches of snow crab from the outep portion of Northeastern Avalon (Area 19) Newfoundland,.
8. 7 6 J z 5 1- - 4 W LU - 3 2 &01 B: 1802 mt. (I434-2914).0 0. 200 400 600 800 1000 1200 1400 1600 1800 2000. CUMULATIVE CATCH (mt) Fig. 6. Leslie graph of biweekly catches of snow crab from Bonavista Bay (Area 25) Newfoundland,.
14 19r-1JmULYY-~A~U~G.~--~r-l(~=mw---~--------------------~ I OCt-NOV. 18 17 16 15 14 13 Y :: 17 53 + (-1'793 x 10-s)X rz:: 0 87 IL :: 40 8 0 :: 917 mt (760-1468) o~~~~~~~-l~~~~~l-l-l-~~j-~~~ 400 500 600 700 800 900 1000 CUMUl ATiVE CATCH (mt) Fig. 7. Leslie graph of biweekly catches of snow crab from Fogo-Cape Freels (Area 28) Newfoundland,.
15 8 JUNE JULY OCT. -NOV. 6 Y : 8-79+ (-8-0I3x 1Q-6) X,2=0 75 " : 49 B.= 1097 mt (845-1874).oJ :::::> ~ 5 0- ct a:: to... 4.x... W :::::> ~ ;; 2 1000 1100 Fi g. 8. Lesl ie graph of biweekly catches of snow crab from Notre Dame Bay (Area 32) Newfoundland,
16 19 IS 17 16 15 14 MAY-JUNE JULY AUG.-SEPT. OCT.-DEC. Y : IS 32+(-9 05SxI0-6 )X r2: 0 77 p. : 60 8 0 : 2023 ml (1632-3023) 13-12...J ;::, ~ II a. ~ 10 ~ ~9... S w ;::, a. 7 u 6 5 4 3 2 00 CUMULATIVE CATCH (ml) 2000 2200. Fig. 9. Lesl ie graph of biweekly catches of snow crab from Horse Islands (Area 34) Newfoundland,
' ^ t V ^2 J 10 9 o7 U. -^ 5 0 4 U 3 2 0 0 --...- 200 400 600 800 1000 1200 1400 1600 1800 CUMULATIVE CATCH. (mfi) Fig. io. Leslie graph of biweekly catches, of snow crab from White Bay (Area 36) Newfoundland,.